Well head stabilizing device and method

Abstract

A device is for stabilizing a well head which includes a well base arranged on a seabed. The well base includes at least a support column, and a first portion of a conductor casing being encircled by the support column, an annulus encircling the first conductor-casing portion being filled with cement, and a second portion of the conductor casing projecting in an elastically flexible manner up from the first conductor-casing portion. A method is for stabilizing a well head which includes a well base arranged on a seabed.

The invention claimed is: 
     
       1. A device for stabilizing a well head on a sea bed, the device comprising:
 a well base having a suction base and a support column formed integrally with the suction base, and 
 a conductor casing having a first portion that is encircled by the support column and a second portion that projects upwardly from the first portion, 
 wherein an annulus is defined between the support column and the conductor casing, the annulus having a lower portion that encircles the first portion of the conductor casing and is filled with cement, and an upper portion that encircles the second portion of the conductor casing and is free from cement such that the second portion of the conductor casing is elastically flexible with respect to the first portion. 
 
     
     
       2. The device according to  claim 1 , wherein the suction base has a closed top and an open bottom, and wherein an underpressure is worked up inside the well base by a water mass enclosed by the well base and the sea bed so that a downward resultant force arises on the well base from the underpressure, which presses the suction base and support column down into an unconsolidated mass below the sea bed. 
     
     
       3. The device according to  claim 2 , wherein the lower portion of the support column rests in a laterally supporting manner against the unconsolidated mass. 
     
     
       4. The device according to  claim 3 , wherein the support column has a continuous contact surface against the unconsolidated mass without any material between the unconsolidated mass and the continuous contact surface. 
     
     
       5. The device according to  claim 4 , further comprising a cementing line that supplies the cement into the annulus along the first portion of the conductor casing. 
     
     
       6. The device according to  claim 5 , further comprising a pump that regulates a level of the cement in the annulus. 
     
     
       7. A device for stabilizing a well head on a sea bed, the device comprising:
 a well base having a support column; 
 a conductor casing having a first portion that is encircled by the support column and a second portion that projects upwardly from the first portion, 
 wherein an annulus is defined between the support column and the conductor casing, the annulus having a lower portion that encircles the first portion of the conductor casing and is filled with cement, and an upper portion that encircles the second portion of the conductor casing and is free from cement such that the second portion of the conductor casing is elastically flexible with respect to the first portion; 
 a packer disposed in the annulus at a distance below a top surface of the sea bed and above the second portion of the conductor casing, wherein the packer prevents cement from flowing up to the top surface via the annulus between the support column and the second portion of the conductor casing; and 
 a cement-diversion system connected to the annulus below the packer and configured to carry away an excess of the cement from the annulus below the packer as the cement fills up the annulus between the support column and the first portion of the conductor casing. 
 
     
     
       8. The device according to  claim 7 , wherein the lower portion of the support column rests in a laterally supporting manner against an unconsolidated mass below the sea bed. 
     
     
       9. The device according to  claim 8 , wherein the support column has a continuous contact surface against the unconsolidated mass without any material between the unconsolidated mass and the continuous contact surface. 
     
     
       10. The device according to  claim 9 , further comprising a cementing line that supplies the cement into the annulus along the first portion of the conductor casing. 
     
     
       11. The device according to  claim 10 , further comprising a pump that regulates a level of the cement in the annulus. 
     
     
       12. The device according to  claim 11 , wherein the conductor casing has a third portion that extends downwardly below the support column into the unconsolidated mass. 
     
     
       13. A device for stabilizing a well head on a sea bed, the device comprising:
 a well base having a support column; 
 a conductor casing having a first portion that is encircled by the support column and a second portion that projects upwardly from the first portion, 
 wherein an annulus is defined between the support column and the conductor casing, the annulus having a lower portion that encircles the first portion of the conductor casing and is filled with cement, and an upper portion that encircles the second portion of the conductor casing and is free from cement such that the second portion of the conductor casing is elastically flexible with respect to the first portion; and 
 a flushing line that flushes the annulus below an uppermost portion of the well base, wherein the flushing line is configured to flush excess cement upwardly out of the annulus alongside the second portion of the conductor casing, while leaving the cement in the annulus alongside the first portion of the conductor casing. 
 
     
     
       14. The device according to  claim 13 , wherein the lower portion of the support column rests in a laterally supporting manner against an unconsolidated mass below the sea bed. 
     
     
       15. The device according to  claim 14 , wherein the support column has a continuous contact surface against the unconsolidated mass without any material between the unconsolidated mass and the continuous contact surface. 
     
     
       16. A method of establishing a well head which includes a well base arranged on a sea bed, the method comprising:
 providing a well base having an integrated suction base and support column; 
 placing the well base on the sea bed and creating an underpressure inside the well base so that a downward resultant force arises on the well base, which presses the suction base and support column down into an unconsolidated mass below the sea bed; 
 lowering a first portion of a conductor casing into the support column; 
 filling an annulus between the support column and the first portion of the conductor casing with cement; 
 providing a second portion of the conductor casing that projects above the support column such that an annulus between the second portion of the conductor casing remains free from cement; and 
 establishing the well head on the second portion of the conductor casing. 
 
     
     
       17. A method of establishing a well head which includes a well base arranged on a seabed, the method comprising:
 driving a support column down into an unconsolidated mass below the seabed; 
 lowering a first portion of a conductor casing into the support column; 
 providing a second portion of the conductor casing that projects above the support column; 
 installing a packer in an annulus between the support column and the conductor casing, the packer being located at a transition between the first and second portions of the conductor casing; 
 filling the annulus between the support column and the first portion of the conductor casing with cement and such that the packer causes the second portion of the conductor casing to remain free from cement; and 
 establishing the well head on the second portion of the conductor casing. 
 
     
     
       18. The method according to  claim 17 , further comprising filling the annulus along the support column and the first portion of the conductor casing by causing the cement to enter a lower portion of the support column. 
     
     
       19. The method according to  claim 18 , further comprising diverting an excess amount of cement out of the annulus along the first portion of the conductor casing through a cement-diversion system connected to the annulus below the packer. 
     
     
       20. A method of establishing a well head which includes a well base arranged on a seabed, the method comprising:
 driving a support column down into an unconsolidated mass below the seabed; 
 lowering a first portion of a conductor casing into the support column; 
 filling an annulus between the support column and the first portion of the conductor casing with cement; 
 providing a second portion of the conductor casing that projects above the support column such that an annulus between the second portion of the conductor casing remains free from cement; 
 flushing an excess of cement upwardly out of the annulus alongside the second portion of the conductor casing, leaving a remaining amount of cement in the annulus alongside the first portion of the conductor casing; and 
 establishing the well head on the second portion of the conductor casing.